In a semiconductor device, a copper plate or a copper alloy plate is used for a lead frame on which to mount a semiconductor element, and the front surface of the lead frame is coated with metal plating, such as gold, silver, nickel, or tin, for the purpose of an improvement in corrosion resistance and heat resistance. Above all, nickel plating is often employed.
Meanwhile, by coating the front surface of the lead frame with metal plating, the adhesion to a molding resin such as an epoxy resin used in transfer molding decreases in some cases. Because of this, it may happen that initial separation occurs between the lead frame and the molding resin immediately after the transfer molding. Also, it is known that the molding resin becomes likely to separate from the lead frame due to the repeated heat stress in the environment of usage.
As a preceding example which has a configuration for improving the adhesion between the metal plating on the front surface of the lead frame and the molding resin, in PTL 1, a package component including a covering surface, which is sealed with an insulating resin, in at least one portion of the front surface is configured so as to have a rough-surfaced plating layer wherein the front surface of the lead frame is covered with a conductive film, and furthermore, wherein the conductive film on the covering surface is roughened (refer to FIG. 13).
Also, in PTL 2, a configuration is such that a plurality of quadrate depressions are disposed in length and breadth at substantially regular intervals by so-called dimpling whereby the lead frame is pressed with a die, thus suppressing separation of the molding resin owing to the anchor effect (refer to FIG. 14).